Solr In Action 笔记(1) 之 Key Solr Concepts

 1 private int doNext(int doc) throws IOException {
 2     for(;;) {
 3       // doc may already be NO_MORE_DOCS here, but we don‘t check explicitly
 4       // since all scorers should advance to NO_MORE_DOCS, match, then
 5       // return that value.
 6       advanceHead: for(;;) {
 7         for (int i = 1; i < docsAndFreqs.length; i++) {
 8           // invariant: docsAndFreqs[i].doc <= doc at this point.
 9 
10           // docsAndFreqs[i].doc may already be equal to doc if we "broke advanceHead"
11           // on the previous iteration and the advance on the lead scorer exactly matched.
12           if (docsAndFreqs[i].doc < doc) {
13             docsAndFreqs[i].doc = docsAndFreqs[i].scorer.advance(doc);
14 
15             if (docsAndFreqs[i].doc > doc) {
16               // DocsEnum beyond the current doc - break and advance lead to the new highest doc.
17               doc = docsAndFreqs[i].doc;
18               break advanceHead;
19             }
20           }
21         }
22         // success - all DocsEnums are on the same doc
23         return doc;
24       }
25       // advance head for next iteration
26       doc = lead.doc = lead.scorer.advance(doc);
27     }
28   }

 1     public Scorer scorer(AtomicReaderContext context, Bits acceptDocs)
 2         throws IOException {
 3       List<Scorer> required = new ArrayList<>();
 4       List<Scorer> prohibited = new ArrayList<>();
 5       List<Scorer> optional = new ArrayList<>();
 6       Iterator<BooleanClause> cIter = clauses.iterator();
 7       for (Weight w  : weights) {
 8         BooleanClause c =  cIter.next();
 9         Scorer subScorer = w.scorer(context, acceptDocs);
10         if (subScorer == null) {
11           if (c.isRequired()) {
12             return null;
13           }
14         } else if (c.isRequired()) {
15           required.add(subScorer);
16         } else if (c.isProhibited()) {
17           prohibited.add(subScorer);
18         } else {
19           optional.add(subScorer);
20         }
21       }
22 
23       if (required.size() == 0 && optional.size() == 0) {
24         // no required and optional clauses.
25         return null;
26       } else if (optional.size() < minNrShouldMatch) {
27         // either >1 req scorer, or there are 0 req scorers and at least 1
28         // optional scorer. Therefore if there are not enough optional scorers
29         // no documents will be matched by the query
30         return null;
31       }
32       
33       // simple conjunction
34       if (optional.size() == 0 && prohibited.size() == 0) {
35         float coord = disableCoord ? 1.0f : coord(required.size(), maxCoord);
36         return new ConjunctionScorer(this, required.toArray(new Scorer[required.size()]), coord);
37       }
38       
39       // simple disjunction
40       if (required.size() == 0 && prohibited.size() == 0 && minNrShouldMatch <= 1 && optional.size() > 1) {
41         float coord[] = new float[optional.size()+1];
42         for (int i = 0; i < coord.length; i++) {
43           coord[i] = disableCoord ? 1.0f : coord(i, maxCoord);
44         }
45         return new DisjunctionSumScorer(this, optional.toArray(new Scorer[optional.size()]), coord);
46       }
47       
48       // Return a BooleanScorer2
49       return new BooleanScorer2(this, disableCoord, minNrShouldMatch, required, prohibited, optional, maxCoord);
50     }